甘肃玉米大斑病菌对嘧菌酯的敏感基线与抗药性监测
Monitoring of resistance and baseline sensitivity of Setosphaeria turcica to azoxystrobin in Gansu

为明确甘肃玉米大斑病菌对嘧菌酯的敏感基线和抗性水平,采用平皿法测定了采自甘肃4个典型生态区的57株玉米大斑病菌对嘧菌酯的敏感性。结果表明,甘肃玉米大斑病菌对嘧菌酯敏感性差异较大,EC50在0.03~5.21 μg/mL之间,平均EC50为0.54 μg/mL,其中有32个菌株EC50呈连续性正态分布,平均EC50为0.10 μg/mL,即为甘肃玉米大斑病菌对嘧菌酯的敏感基线。基于此,发现12株抗性菌株,平均抗性水平为5.18,最高抗性水平为49.93,抗性频率为21.05%,其中南部湿润和陇东半湿润半干旱地区出现中、高抗菌株7株,占12.28%,陇东半湿润半干旱和中部干旱雨养地区出现低抗菌株5株,占8.77%,而河西干旱灌溉地区15株菌对嘧菌酯十分敏感,平均抗性水平为1.56,最高抗性水平为3.89,暂抗药性。
The sensitivity of 57 isolates of Setosphaeria turcica to azoxystrobin in four typical ecological regions in Gansu was tested with Petri plate in order to determine their sensitive baseline and resistance factor. The results showed that the sensitivity of S. turcica to azoxystrobin in Gansu was greatly different:EC50 range was 0.03-5.21 μg/mL, and the average of EC50 was 0.54 μg/mL. The sensitive baseline of S. turcica to azoxystrobin in Gansu was 0.10 μg/mL only when normality test of EC50 on 32 isolates was continuous normal distribution. On the base of sensitive baseline, it was found that 12 isolates of S. turcica in Gansu was resistant to azoxystrobin; the highest and average resistance factor were 49.93 and 5.18, and the resistance frequency was 21.05%. Thereinto, seven highly and moderately resistant isolates appeared in southern humid areas and east semi-humid and semiarid areas, accounting for 12.28%; five lowly resistant isolates appeared in east semi-humid and semiarid areas and central rainfed dryland, accounting for 8.77%, but 15 isolates of S. turcica in irrigated dryland of Hexi Corridor was very sensitive to azoxystrobin:the highest and average resistance factor was 3.89 and 1.56 respectively, and there was no resistance.